Substance use treatment; Treatment for co-occurring substance use plus either serious mental health illness in adults/serious emotional disturbance in children; Outpatient; Intensive outpatient treatment; Does not use medication assisted treatment for alcohol use disorder; Does not treat opioid use disorders; Anger management; Cognitive behavioral therapy; Contingency management/motivational incentives; Motivational interviewing; Matrix Model; Relapse prevention; Substance use disorder counseling; Telemedicine/telehealth therapy; Trauma-related counseling; 12-step facilitation; Private non-profit organization; State department of health; Commission on Accreditation of Rehabilitation Facilities (CARF); Federal, or any government funding for substance use treatment programs; Medicaid; Private health insurance; Cash or self-payment; Adolescents; Clients with co-occurring mental and substance use disorders; Comprehensive mental health assessment; Comprehensive substance use assessment; Screening for substance use; Screening for mental disorders; Drug or alcohol urine screening; Discharge Planning; Mentoring/peer support; Treatment for other addiction disorder; Substance use disorder education; Individual counseling; Group counseling; Family counseling; Smoking not permitted; Children/adolescents; Female; Male; Spanish; Vaping not permitted; Mental health services; Social skills development; Suicide prevention services